The hyperthermophilic archaeon Pyrococcus furiosus possesses a modified Embden—Meyerhof pathway, including an unusual ADP-dependent glucokinase (ADP-GLK) and an ADP-dependent phosphofructokinase. In the present study, we report the characterization of a P. furiosus galactokinase (GALK) and its comparison with the P. furiosus ADP-GLK. The pyrococcal genes encoding the ADP-GLK and GALK were functionally expressed in Escherichia coli, and the proteins were subsequently purified to homogeneity. Both enzymes are specific kinases with an optimal activity at approx. 90°C. Biochemical characterization of these enzymes confirmed that the ADP-GLK is unable to use ATP as the phosphoryl group donor, but revealed that GALK is ATP-dependent and has an extremely high affinity for ATP. There is a discussion about whether the unusual features of these two classes of kinases might reflect adaptations to a relatively low intracellular ATP concentration in the hyperthermophilic archaeon P. furiosus.
Biochemical adaptations of two sugar kinases from the hyperthermophilic archaeon Pyrococcus furiosus
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Corné H. VERHEES, Denise G.M. KOOT, Thijs J.G. ETTEMA, Cor DIJKEMA, Willem M. de VOS, John van der OOST; Biochemical adaptations of two sugar kinases from the hyperthermophilic archaeon Pyrococcus furiosus. Biochem J 15 August 2002; 366 (1): 121–127. doi: https://doi.org/10.1042/bj20011597
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